Giardia needs to be done more than once , weeks apart .
Are there concerns such as soupy stools , weight loss, lethargy ? I may have missed previous posts .
If it is a matter of eating and that worrying you , that is another matter.

I may put out a thread on feeding. Just finished reading a study done in the late 70's which looked at large dogs vs small dogs , caloric needs in relation to nutritional needs.
The problem is that once the caloric needs are met there is a satisfaction , satiation point, where the dog will stop eating . That , though, may well be below the nutrition needed for a large , quickly growing dog !!!!

So for GSD it appears , calorie conservative --- nutrient value HIGH .